Comcast landline number is being spoofed

My Comcast landline number is being spoofed. Came home one evening and had a voice mail from a lady screaming "I wish you people would leave people alone that do not need your service...STOP CALLING ME STUPID PEOPLE". I called this lady back to tell her nobody called her from this number because no one was home. I asked her what did the person say. She said they were talking about a student loan. I have received numerous calls with the pre-fix of my landline number. My caller ID will show a name, sometimes a business, a city and state, not available. Today I received a call that had 11 in front of the area code and then the 3 digit pre-fix of my phone number and the last four digits (not mine). I don't know what 11 in front of an area code does. I have been receiving calls with the same 3 digit pre-fix as mine all year. I had a an idea that my landline could have been spoofed when I begin noticing on my caller ID calls from people I didn't know and all the calls I were receiving with the same 3-digit pre-fix number as mine. The voice mail confirmed that yes, my comcast landline is being spoofed.

I called Comcast and no help only that I could pay more money for something she offered. I declined.